why are you worried about having the same rep across all your toons?
personally it saves me from having to name all my alts and main on different variations of the same name. and i don't have tot ell people "hey it's me dirtyklingon!" and have them worry about me trying to scam or dupe them somehow cuz they're not sure if it's really me or not.
For one thing, it deters griefers from anonymously spamming insults and/or derogatory comments. Also, you 'friend' and 'ignore' by the account. I must say, I prefer this method. I've met too many morons in games.
They do the exact same thing in Guild Wars. when you joined a guild the first toon that you got accepted with is the name that is tagged to all of your alts. And you could only be in one guild no matter hwo many alts you had. I have also noticed that when a person on yoru friends list logs in it jsut says that the account is online and doesnt' say which toon they are playing.